Journal: bioRxiv
Article Title: Collagen I promotes cancer cell survival via amino acid import and mTORC1 activation
doi: 10.1101/2025.11.26.690708
Figure Lengend Snippet: (A) MDA-MB-231 and PANC1 cells were seeded on 2 mg/ml collagen I and treated with 5 µM, 10 µM BTT-3033 (BTT) or DMSO (Ctrl) for 4 days under Glc starvation. (B) MDA-MB-231 and PANC1 cells were seeded on 2 mg/ml collagen I and transfected with an siRNA targeting β1 integrin (β1 si), an siRNA targeting α2 integrin (α2 si) or a non-targeting siRNA control (Nt si) for 4 days under Glc starvation. Cells were fixed and stained with Hoechst 33342. Images were collected by ImageXpress micro and analysed by MetaXpress software. (C) MDA-MB-231-GFP spheroids were generated by the hanging drop method, embedded in 3 mg/ml collagen I and Geltrex (50:50) mixture and starved in Glc-free media for 2 days, in the presence of 10 µM BTT-3033 (BTT) or DMSO (Ctrl). Live images were collected by a Nikon A1 Confocal microscope. (D) MDA-MB-231-GFP cells were transfected with an siRNA targeting α2 integrin (α2 si) or a non-targeting siRNA control (Nt si) for 24 hours. Spheroids were generated by the hanging drop method, embedded in 3 mg/ml collagen I and Geltrex (50:50) mixture in Glc starvation media for 3 days. Live images were collected by a Nikon A1 Confocal microscope. (E) PANC1 spheroids were generated by the hanging drop method, embedded in 3 mg/ml collagen I and Geltrex (50:50) mixture in Glc starvation media for 6 days in the presence of 10 µM BTT-3033 (BTT) or DMSO (Ctrl). Spheroids were imaged live every 2 days with an Olympus E45O microscope. (F) PANC1 cells were transfected with an siRNA targeting α2 integrin (α2 si) or a non-targeting siRNA control (Nt si) for 24 hours. Spheroids were generated by the hanging drop method, embedded in 3 mg/ml collagen I and Geltrex (50:50) mixture in Glc starvation media for 6 days. Live images were collected by an Olympus E45O microscope. (G, H) E0771 mouse tumour organoids were grown in a 3 mg/ml collagen I and Geltrex (50:50) mixture in Glc starvation media for 3 days in the presence of 2.5 µM, 5 µM BTT-3033 (BTT) or DMSO (Ctrl). Spheroids were imaged live every day with an Olympus E45O microscope. Bar, 250 µm. Data are presented as mean ± SEM, N=3 independent experiments, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; (A, B and H) Kruskal-Wallis, Dunn’s multiple comparisons test; (C-G) Two-way ANOVA, Tukey’s multiple comparisons test.
Article Snippet: Primary antibodies for Phospho-S6 Ribosomal Protein ser235/236 and LC3A/B were from Cell Signalling; α2 integrin (CD49b)-FITC conjugated and β1 integrin (CD29)-Alexa Fluor 488 conjugated from BioLegend; α2 integrin for Western blotting from BD-bioscience; SLC3A2 (CD98) and SLC7A5 (LAT1) from Proteintech and GAPDH from SANTA CRUZ Biotechnology.
Techniques: Transfection, Control, Staining, Software, Generated, Microscopy